The present invention is directed to a transmission-reception separating filter having a transmission channel for forwarding a high-frequency current from a transmitter to an antenna, whereby a PIN diode is arranged in the transmission channel.
Transmission-reception separating filters are used to optionally connect a transmitter or a receiver to an antenna. A transmission-reception separating filter thus is an antenna switch and electrically corresponds to a mechanical switch. The use of PIN diodes in antenna switches or, respectively, transmission-reception separating filters is disclosed in the book by Erich Renz, "PIN und Schotty-Dioden", Heidelberg, 1976, pages 121 and 122. PIN diodes are well-suited as high-frequency switches because they have a low insertion attenuation in an "on" state and a high blocking attenuation in an "off" state In the Erich Renz reference, however, the control current for controlling the PIN diode in the transmission channel is supplied by an external voltage source. As a result the transmission-reception separating filter has a complex circuit configuration.